Sensors used: adafruit SGP40 gas, adafruit SHT31D temp/humidity.

cron job runs every minute

• • • • • • python3 /home/pi/VOC_monitor/VOC_log.py USERNAME KEY

saves log to VOC_monitor.txt, dumps to IOT services then terminates.

VOC index levels and how to handle the levels.

    :note    0-100,no need to ventilate, purify
    :note    100-200,no need to ventilate, purify
    :note    200-400,ventilate, purify
    :note    00-500,ventilate, purify intensely

used Sensirion example files as the base of this. included below and kept for prosperity.

https://github.com/itsnils/Sensirion_SGP40

Sensirion SGP40 Python 3.x Library

With this library you can read out the VOC index from the Sensirion SGP 40 Sensor.

Installation: Connect the Sensirion SGP40 sensor to the Raspberry Pi.

• GND
• VDD
• SDA
• SCL

note that I2c is switched on on your Raspberry Pi.

Attention. if you sudo i2cdetect -y 1 the sensor will not be displayed. this does not mean that the sensor is not working.

Download the files and run sudo python3 example_sgp40_voc_index.py the allgerutmuss now calculates with a default value of 50 %rh and 25°C

To achieve a more realistic accuracy you can connect a SHT30 sensor and run sudo example_sgp40_and_sht30_voc_index.py You can of course also use another temperature and humidity sensor. To do this, change sgp40.set_envparams() in the loop